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Home -> Community -> Mailing Lists -> Oracle-L -> Re: Snapshot too old during stress test... how to avoid
Speaking of this trick with a txn in each RBS, I've got a shell script on my
website (http://www.evdbt.com/tools.htm) that does just that. It is named
"prevent1555.sh" which uses a stored procedure created by a SQL script named
"prevent1555_ddl.sql"...
As Jared mentioned, it is kind of a last resort, but it works...
on 6/4/03 4:05 PM, Jared.Still_at_radisys.com at Jared.Still_at_radisys.com wrote:
> .. and if it still doesn't work, use the trick of putting a transaction
> in
> each of the rollback segments while the system is otherwise quiesced,
> and *do not* commit or rollback the transactions.
>
> This forces the rollbacks to extend if necessary, they will never wrap
> back to the first extent ( actually the second) as long as those
> transactions
> are not committed.
>
> It just uses a lot of disk space. Disk is cheap, right? :)
>
> Consider offlining all your production RBS and creating temporary ones
> that you can easily drop later.
>
> I've used it with SAP client copies, which will not run to completion
> without
> doing this, at least on our system.
>
> Jared
>
>
>
>
>
> Kirtikumar Deshpande <kirtikumar_deshpande_at_yahoo.com>
> Sent by: root_at_fatcity.com
> 06/04/2003 09:45 AM
> Please respond to ORACLE-L
>
>
> To: Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com>
> cc:
> Subject: Re: Snapshot too old during stress test... how to avoid
>
>
> Try removing optimal setting, and shrinking RBS to the min extents (or
> even below) before running
> your tests.
>
> - Kirti
>
>
> --- Garry Gillies <g.gillies_at_weir.co.uk> wrote:
>> From memory (of a course attended looong ago), >> Oracle recommends one rollback segment for every >> three to four users. >> Four rollback segments between thirty six processes >> does seem a little mean. >> >> Garry >> >> >> >> >> >> <rgaffuri_at_cox.net> >> Sent by: root_at_fatcity.com >> 04/06/03 13:59 >> Please respond to ORACLE-L >> >> >> To: Multiple recipients of list ORACLE-L
> <ORACLE-L_at_fatcity.com>
>> cc: >> Subject: Snapshot too old during stress test... how to
>> >> >> Im testing worst case scenarios right now. So Im doing batch >> updates,inserts,deletes and 'create table as' from a staging tablespace
>> approximately 5GBs to a master tablespace of approximately 11GBs. >> >> Ive got my job queue processes set to 36 and Im running 36 at a time in >> the background in order to gather statistics and timing under worst case
>> scenarios. >> >> Im in 8.1.7.3 and I have increased the size of my RBS tablespace to 11GB
>> for this test. I have 4 standard RBS with optimal size set to 1GB. Why >> would I get a snapshot too old? I would think that 11GBs of rollback
>> be big enough. Would increasing the number of Rollback segments avoid
>> even though I have the same amount of space in the tablespace? >> >> In reality Im going to seriallize the process to avoid this and to
>> performance, however, I want to stress the system. >> >> any advice? >> >> -- >> Please see the official ORACLE-L FAQ: http://www.orafaq.net >> -- >> Author: <rgaffuri_at_cox.net >> INET: rgaffuri_at_cox.net >>
-- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Tim Gorman INET: tim_at_sagelogix.com Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).Received on Thu Jun 05 2003 - 02:25:36 CDT
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